Application of Vortex Dynamics Diagnosis in Numerical Simulation of Tubular Turbine

Abstract

In order to study the interaction of vortex structure,vortex evolution and vortex in a tubular turbine,the regularized helicity, Q-criterion and BVF diagnosis based on RNG k −e turbulence model and vortex dynamics diagnosis method are applied to a tubular turbine under certain working conditions.The vortex motion was numerically studied. Turbulent vortex movements dominate the turbine operation. Compared with the cloud diagrams of pressure,streamline and velocity observed by the numerical methods, the vortex dynamics diagnosis can accurately capture the vortex structure,the distribution of vortexes and the intensity variation of the turbine runner and the draft tube. By applying the vortex dynamics criterion,it is found that there is a vortex in the direction of rotation and the flow direction of the water flowing near the water inlet edge and the hub of the front runner of the turbine runner. At the back of the hub,there is a vortex with a direction of rotation and a direction of flow opposite the inlet. The application of vortex dynamics diagnosis found that the flow separation zone and the BVF peak zone on the turbine runner blades are more accurate than the traditional analysis methods.The application of vortex dynamics diagnosis on the tubular turbine provides a new perspective for turbine runner optimization and a new idea for changing the flow in the digital turbine.